Resonance-receiving relay switching device



July i9, 1949. f w. KoENxG 43759419 RESONANC-RECEIVING RELAY SWITCHING DEVICE Filed March 28, 1945 1 v I T 217,70 AgRNFYs Patented July 19, 1949 RESONANCE-RECEIVING RELAY SWITCHING DEVICE Werner Koenig, Lucerne, Switzerland, assignor to Landis & Gyr, A. G., Zug, Switzerland, a body corporate of Switzerland Application March 28, 1945, Serial No. 585,363 In Switzerland November 16, 1943 Claims.

The utilization of audio-frequency heterodyne methods for distant control of tariif apparatus, hot water boilers, etc. is known per se in the art. Particularly advantageous in this field is the method of operating with only a single sending frequency employing various impulse series for differentiating the control orders, such impulse series acting correspondingly on selective receivers. The meritsgof this procedure lie on the one hand in the practically unlimited number of different possibilities of orders, and on the other hand in the comparatively simple and consequently economically favorable sending apparatus. On the receiving end, however, the economical aspect of the single-frequency selection method, in contradistinction to the multi-frequency procedure, depends to a very great extent on the number of different control orders for which the single receiving apparatus of a plant is best adapted. Since the fundamental equipment comprising the resonance-receiving means and the selector remains (independent of the number of control orders to be worked by the individual receiving instrument) always the same, the expense for each on/oii-double-order switch will be more, the greater the expenditure for the fundamental outfit and the smaller the number of operations of the corresponding receiving instrument. In the case of receiving apparatus principally adapted for a few operations, it is therefore advantageous with the single frequency procedure for the fundamental equipment to necessitate as slight an expenditure as possible. In its essentials this fundamental outfit consists of the resonance receiving means serving to filter the weak audio-frequency impulses from the mixture of line voltage and control voltage and to convert them into heavy current impulses. A well-known arrangement for the resonance receiving part utilizes a series-resonance circuit consisting of a condenser, a choking coil, a rectifier whose A. C. feed is connected to the taps of the choking coil, and a sensitive D. C. relay excited through the rectifier by the audio-frequency impulse currents. An objection raised against this arrangement is that it involves a considerable expense and the jeopardizing of the rectifier by overvoltage.

According to the present invention this drawback is obviated by the fact that a specially designed A. C. relay is provided in series with a condenser connected to the line, the two constituting together a series-resonance circuit tuned to the superimposed frequency. Thereby the specially designed A. C. relay replaced in the known arrangement the choking coil, the rectifier and the D. C. relay and is excited immediately by the audio-frequency impulse.

In the accompanying drawing there is shown by way of example one constructional form of the VTo obtain a convenient tuning by varying the 2 relay incorporating the invention, in diagrammatic representation.

Fig. 1 is a wiring diagram of the receiving set, and

Fig. 2 exhibits an example of embodiment of the resonance-receiving relay.

As shown in Fig. l there lies between a network A, B a series-resonance circuit including a receiving relay IUI and a condenser |02. Thereby the resonance relay IUI is together with the condenser IGZ tuned to the emission frequency. It has a contact device III which makes the selector IGS active. In the figure, this selector is only schematically illustrated and may be designed as motor selector or as step selector. Through this selector ID3, individual order relays, say |04 and IS, are actuated which are fitted with corre'- sponding contacts IM and ISI. In this gure this order relay is represented, for example, as a switching one.

Fig. 2 represents an embodiment of the resonance receiving relay. In order that this special A. C. relay be able to take over the part of a good reactor in the resonance circuit, it must have above all a high quality factor Q=(wL) zr. In addition to the utilization of the well-known measures of laminated iron cores and the disposition of a suitably selected air gap, this was achieved in the first instance by the fact that the structural parts penetrated by the stray field, such as end plates of the iron packs, supports, etc. consist of insulating material. In Fig. 2 only the rear end plate has been illustrated for the sake of clearness.

The tuning of the series-resonance circuit to the emission frequency could, in principle, be just as well obtained by varying both the capacity and the inductivity. But, since the usual paper condensers are obtainable only with xed capacity values, the tuning by altering the inductivity appears to be the more preferable method. Now, according to this invention the tuning is brought about by the A. C. relay I designed as reactor through the medium of a variable air gap 3 lying in series with the armature air gap 2.

series-air gap 3 with simple constructural forms, the stator core is divided into two L-shaped parts 4 and 5, of which the core part 4 is fixedly attached to the supporting elements, whereas the core part 5 is pivoted around the armature shaft 6 as a rotary axis. This pivoting movement about the shaft 8 as an axis can occur because the core part 5 has grooves 32 which permit the core to be moved relative to bolts extending through the grooves and fastened to the end plate 1. In order that the air gap 2 may remain intact when the adjustable core part 5 is swung, the end plates of isolating pressed material are each provided with a circular elevation on the side facing the `ore. These elevations of the end plates exhibit ith respect to the armature a greater diameter which is double that of the armature air gap, and project somewhat into the cylindrical hollow space formed by the two core parts 4 and 5. Oi these two end plates only the rear end plate 'l with the elevation 1I is shown in Fig. 2. The end plates also are provided with bores for journallng the armature axis 5 in a concentric position to the elevations. When assembling and on tuning, a slight pressure applied to the core parts 4 and 5 against the circular elevations of the end plates with subsequent tightening of the pressure screws suhice for obtaining an accurate centering of the armature 8 and for ensuring the prescribed air sap 2.

As apparent from Fig. 2, the A. C. receiving relay is designed as rotary armature relay. In contradistinction thereto, the well-known A. C. relays are generally constructed as flap armature relays whose magnetic driving flux is .partly linked up with a short-circuit winding for the purpose of avoiding the A. C. noise. Such aap armature relay, however, is hardly suitable for the purpose here, as it involves comparatively `heavy power losses due to the 'short-circuit winding. On 'the other hand, however, provision must also be made on the rotary armature relay to avoid any tendencies to oscillation. By utilizing the rotary .armature relay as reactor in a resonance circuit, the tendency .to oscillation is particularly yfavoured by the increase of the mag netic flux and consequently of the inductivlty when .the armature is pulled. The increased lna corresponding decrease of the relay torque. According to the present invention these diliculties are remedied by the yfollowing measures which aim throughout at a reduction or the relative .armature position. 'By means of a magnetic shunt 9 bridging the armature 8, the ratio 'of the armature flux varying with the armature position to the total flux is reduced. As a result, the rela-tive change of the induction of `the relay wind-ing as Ia function of the armature position Vis reduced. By this magnetic shunt 9, however, an extra magnet-ic field is set up which in turn creates an additional induced voltage in a relay coil lli. Although a reduction of the quality factor Q is not involved therewith, .since the reactive input also is simultar-ieously increased, an increment .oi the active losses is always undesirable. In order vto :maintain these in 'as narrow bounds ,as possible, according to the invention the .already existent and otherwise injurious stray flow is resorted to. To this end the stray rflow is caught .up by a suitable screen plate Il and directed into desired paths. This screen plate is made of magnetically high-quality material so vthat the losses ycaused vby leakage will Vremain sniailer in spite .of the artificial increase of the stray yflow than if .the unconducted stray vlines were to penetrate any metal parts in the vicinity .of the relay, say supporting elements. By this measure a .protection is simultaneously provided against accidental .or `deceptive influences on vthe receiving relay `from outside.

The .dependence of the vi-nductivity Ion the armature position is further reduced by `selecting a small .useful angle .of torsion armature, that is to noti-oily utilizing the angle of torsion possible with notary armature relays. Further, the unutilized portion ofthe possible armature .angle or torsion is .brought on the side of the .rest posiductivity eects a detuning of the resonance with 1 alteration of the inductivity 'in function of 'the 4 tion of the armature, whereby the same eiect is physically attained as that of a magnetic shunt to the relay armature, viz. an additional flux independent of the armature position.

To suppress any tendency of armature oscillation even in particularly diicult cases, such as may crop up with inconstant emission frequency, a disc l2 with sufficient body inertia is loosely located on the armature axis 6, i. e. on a hub which in turn is rigidly mounted thereon. This disc l2 is effective only when the acceleration of the armature 8 exceeds that limiting value at which the disc l2 begins to slip on the hub i3, whereby the ensuing friction action rapidly suppresses every oscillation. At the same time this disc l2 offers an effective protection against chatter of the armature 8 in the end positions.

Sensitive relays, such as the above described one, have the disadvantage that the armature is inclined to stick in the end positions and, as a matter of fact, in cases in which there is no questien of magnetic sticking due to residual magnetisnl, after lengthy operation or even when unused, under atmospheric influences, there appear adhesive forces on the abutments which may @Qual the order of magnitude of the armature driving forces. A movable roller-shaped membei lli is provided in an aperture l5 of the relay armature 8 to minimize the adhesive forces existi'lg between the .armature and the stops against which it strikes. The aperture l5 is large enough 'to provide a great amount of play between it and the member Id, so that as the armature rotates the member I4 ViS free to move about in the aperture and apply slight taps to the armature to preF vent the gradual accumulation of adhesive forces. The ends o f the member I4 are loosely held in the two end plates by appropriate cylindrical cavities. The rotary angle of the armature 8 can always be adapted to the tuning frequency desired for the relay by changing the diameter of the member M.

Qn the `forward extremity of the armature axis there is also rigidly mounted on axis 6 a cam I5 which, upon rotation of the armature axis 6, Acauses .the contact .device l l to operate. The contacting arms of the device ll are made from springlike material such that they will normally be separated fromeach other.

The arrangement .described hereinbefore is extremely insensitive to overvoltage, due to the absence o f a rectifier. Such overvoltages may arise with heterodyne distant control -plants when the impulse voltage at the receiving Eric undergoes an vuni I ltentional rise owing to resonance `I-lrsl.ellolneifia in some parts of the network which may attain :the multiple of the normal control voltage value. As -a protection against such excess voltages the condenser would have to be .considerably more resistant to voltage and `consequently more expensively dimensioned than -is `required by normal service. Instead, according to the invention, the iron core Vof the relay l is provided with a constriction preferably in the shape .o f a perforation i8 `in the rigid core part 4 in the Icentre io i Athe .coil lu. This constriction is so proportioned that with the normal impulse voltage 'the iron core is Anot vyet saturated. On the other hand, an oyer-rise in the impulse voltage .causes at the point .of constriction as saturation which increases in :the measure as the voltage rises, [a .corresponding decrease of the induc- -tivity of coil zia, by which the resonance circuit consisting of reactor |01! '.(Fig. 1) and condenser M2 gets detuned. As a result, the kcurrent in the resonance circuit which includes the winding l0 increases only slightly even with extreme overvcltages above that value obtained from a normal impulse voltage. The particular advantage' of this self-acting current limitation is seen in the protection of the condenser on the one hand, and on the other hand, in the attainment of a chatter-free relay whose time of response is extensively independent of the impulse voltage.

While I have described a specific embodiment of my invention it is to be understood that the details oi construction may be changed by those skilled in the art within the purview of this invention.

What I claim is:

1. Resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, a stator having a coil wound thereon, a condenser, and means connecting said condenser to said coil so that the condenser and coil are resonant at the foreign frequency, said stator having a variable air gap whereby the relay may be tuned to the superposed frequency.

2. Resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, a stator having a coil wound thereon, a condenser, and means connecting said condenser to said coil so that the condenser and coil are resonant at the foreign frequency, said stator having an air gap at the rotor and a variable air gap whereby the relay may be tuned to the superposed frequency.

3. A relay as claimed in claim 1 in which a portion of the stator is mounted for pivotal movement about the armature.

4. A relay as claimed in claim 1 in which the stator is formed as two L-shaped members, with said air gaps at their adjacent portions, one of said members being mounted for pivotal movement about the axis of the armature.

5. A resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, a stator formed of two L-shaped parts having an air space between adjacent parts, one air space being at the armature, a coil wound on one part of said stator, a condenser, and means connecting said condenser to said coil so that the condenser and coil are resonant at the vforeign frequency, one part of said stator being pivotally mounted whereby one of the air gaps may be varied to tune the relay.

6. A resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, a stator formed of two L-shaped parts having an air space between adjacent parts, one air space being at the armature, a coil Wound on one part of said stator, a condenser, means connecting said condenser to said coil so that the condenser and coil are resonant at the foreign frequency, one part of said stator being pivotally mounted whereby one of the air gaps may be varied to tune the relay, and a magnetic shunt bridging said stator parts so as to be in parallel with said armature and the adjacent air space.

7. A resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, 'a stator formed of two L-shaped parts having an air space between adjacent parts, one air space being at the armature, a coil wound on one part of said stator, a condenser in series with said coil, one part of said stator being pivotally mounted whereby one of theI air gaps may be raned to tune the relay, and end plates of insulating material penetrated by the stray flux.

23. A resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, a stator .formed of two L-shaped parts having an air space between adjacent parts, one air space being at the armature, a coil wound on one part of said stator, a condenser, means connecting said condenser to said coil so that the condenser and coil are resonant at the foreign frequency, one part of stator being pivotably mounted whereby one of the air gaps may be varied to tune the relay, a shaft for the armature, a hub on the shaft and a damping disc loosely carried by the hub.

9. Resonance-receiving alternating current re- ?.ay for the reception of a foreign frequency including, in combination, a pivotable armature, a stator having a coil wound thereon, a condenser, and means connecting said condenser to said coil so that the condenser and coil are resonant at the foreign frequency, said stator having a variable air gap whereby the relay may be tuned to the superposed frequency said rotor being provided with an aperture parallel to its axis, a member loosely carried in said aperture and side plates of insulating material in which the rotor and stator are mounted and forming a stop for said loosely carried member.

10. A resonance-receiving alternating current relay for the reception of a foreign frequency including in combination a pivotable armature, a stator formed of two L-shaped parts having an air space between adjacent parts, one air space being at the armature, a coil wound on one part of said stator, a condenser in series with said coil, one part of said stator being pivotably mounted whereby one of the air gaps may be varied to tune the relay, and an aperture in the stator part holding said coil and substantially in the center of said coil to constrict the cross section of the stator,

WERNER KOENIG.

REFERENCES CITED The following references are of record in the flle of this patent:

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